JPH0932U - Inner wall of metal filtration chamber - Google Patents

Abstract

(57) [Abstract] [Problem] To prevent oxidation in a filtration chamber. SOLUTION: The inner wall of a brick of a filtration chamber for filtering a molten metal such as aluminum, zinc or copper while heating it with a heater, and the molten metal enters a silicon nitride-bonded silicon carbide refractory having excellent corrosion resistance. The inner wall of the metal filtration chamber in which the portion of the heater that receives radiant heat is made of an alumina refractory or a silicate-bonded silicon carbide refractory having excellent oxidation resistance.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to the inner wall of the filtration chamber for molten metal such as aluminum, zinc or copper.

[0002]

[Prior art]

Japanese Patent Laid-Open Publication No. 60-142190, which is publicly known, discloses an invention in which all parts that come into contact with a molten metal are silicon nitride-bonded silicon carbide refractories. Further, in the related art, Japanese Patent Application Laid-Open No. 2-34732 discloses an invention in which the inner surface of the filtration chamber is made of a refractory having SiO ₂ of 5% or less such as silicon carbide bonded to silicon nitride or alumina brick. ing.

[0003]

[Problems to be solved by the device]

In the above-mentioned known ones, all the parts that come into contact with the molten metal are made of silicon nitride-bonded silicon carbide refractory, or the inner surface of the filtration chamber is made of silicon nitride-bonded silicon carbide or alumina bricks containing 5% of SiO _2. In the invention with refractory below, the inner wall is the brick inner wall, the outer wall is a ceramic fire-resistant outer wall, the castable layer is between the inner wall and the outer wall, and the front and rear walls and the left and right walls are surrounded by thin iron plates. Although the silicon nitride-bonded silicon carbide refractory has been used for many years, there was a problem that a gap due to oxidation was formed between the layers forming the inner wall. It was said that the cause of the gap was due to thermal expansion and thermal contraction, but oxidation is also one of the causes. That is, the silicon nitride-bonded silicon carbide refractory exhibits extremely strong corrosion resistance against molten metal such as aluminum and is also resistant to acids and alkalis, but it is problematic in expansion due to oxidation. There is. About one-fifth of the upper part of the filtration layer is not filled with the molten metal and is directly heated by the radiation of the heater, so that part becomes a high oxidizing atmosphere, and the silicon nitride-bonded silicon carbide refractory is formed. But it oxidizes and expands, creating gaps. On the other hand, although the alumina-based refractory or the silicate-bonded silicon carbide refractory has excellent oxidation resistance, the corrosion resistance does not reach that of the silicon nitride-bonded silicon carbide refractory.

[0004]

[Means for Solving the Problems]

 Therefore, according to the present invention, the inner wall of the brick of the filtration chamber, which filters the molten metal such as aluminum, zinc, or copper while heating it with the heater, uses the silicon nitride-bonded silicon carbide refractory having excellent corrosion resistance at the molten metal entering portion. The inner wall of the metal filtration chamber made of an alumina refractory or a silicate-bonded silicon carbide refractory having excellent oxidation resistance is used as a part of the heater which receives radiant heat without entering.

[0005]

【Example】

 An embodiment of the present invention will be described with reference to the drawings, in which 1 is a filtration tank for filtering a molten metal such as aluminum, zinc or copper, and 2 is a filtration unit housed in the filtration tank 1. As shown in FIG. 3, the filtration unit 2 includes a ceramic tube 5 made of an alumina porous tube between a front side plate 3 and a rear side plate 4 made of a silicon carbide refractory plate and several stages above and below. The shape is such that several pieces are crossed over on the left and right.

Although the filtration tank 1 for accommodating the filtration unit 2 is formed in various sizes, the one shown in FIGS. 1 and 2 can accommodate four sets of the filtration units 2 in parallel on the left and right sides. It is a large size having a filtration chamber 6. Therefore, the front and rear sides of the filtration chamber 6 are formed to be larger than the widths of the front side plate 3 and the rear side plate 4 of the filtration unit 2, but the left and right sides are formed longer, and the bird's-eye view shape is a rectangle that is long in the left and right. , 7 is a hot water supply port leading to the filtration chamber 6, 8 is a hot water outlet from the filtration chamber 6, 9 is a front wall of the filtration chamber 6, 10 is a rear wall of the filtration chamber 6, 11 is a left wall of the filtration chamber 6, and 12 is It is the right wall of the filtration chamber 6.

The front wall 9, the rear wall 10, the left wall 11, and the right wall 12 have an inner wall as a brick inner wall 14, an outer wall as a ceramic fireproof outer wall 15, and a castable layer between the brick inner wall 14 and the ceramic fireproof outer wall 15. A three-layer structure having 16 layers is provided, and all or part of the outside of the front wall 9, the left wall 11, and the right wall 12 is surrounded by a thin iron plate 13.

Then, in the filtration chamber 6, about 4/5 of the molten metal enters, and about 1/5 of the upper portion is exposed. The exposed portion is easily oxidized by receiving radiant heat from the heater 21, and if oxidized, the volume expands and causes damage. Therefore, the present invention uses a material for a portion containing molten metal and a portion for not containing molten metal. In other words, it prevents the oxidation of the part where the molten metal does not enter.

That is, in the brick inner wall 14, the portion where the molten metal enters is a silicon nitride-bonded silicon carbide refractory 17 having excellent corrosion resistance, and the portion where the molten metal does not enter and which receives the radiant heat of the heater is made of alumina having excellent oxidation resistance. A refractory material or a silicate-bonded silicon carbide refractory material 18 is used. Reference numeral 19 is a lid of the filtration tank 1, 20 is a lower surface, and 22 is a communication hole.

[0010]

[Action]

 Next, the operation will be described. When a molten metal such as aluminum is supplied from the hot water supply port 7, the molten metal passes through the plurality of upper and lower communication holes 22 and fills the respective filtration chambers 6 on the left and right sides, and is filtered by the ceramic tube 5 while being heated by the heater 21. It is purified and taken out from the hot water outlet 8.

Then, the molten metal is filled in about 4/5 of the filtration chamber 6, about 1/5 of the upper portion is not filled with molten metal, and the portion not filled with molten metal directly receives the radiant heat of the heater 21. However, in the present invention, the part where the molten metal does not enter is changed to alumina refractory material or silicate-bonded silicon carbide refractory material 18, so that it is not oxidized. However, since the expansion due to oxidation is prevented and the portion where the molten metal enters is formed by the silicon nitride-bonded silicon carbide refractory 17 having excellent corrosion resistance, it can well withstand permanent use.

[0012]

【effect】

As described above, in the publicly known Japanese Patent Laid-Open No. 60-142190, there is described an invention in which all portions that come into contact with the molten metal are made of silicon nitride-bonded silicon carbide refractory, and Japanese Laid-Open Patent Publication No. 2-34732. The publication describes an invention in which the inner surface of the filtration chamber is made of a refractory material having a SiO ₂ content of 5% or less, such as silicon carbide bonded to silicon nitride or alumina bricks. However, if all the parts are made of silicon nitride-bonded silicon carbide refractories, there is a problem in the oxidation of the part heated by the heater that does not enter the molten metal, and all parts are made of silicon nitride-bonded silicon carbide or silicon carbide. Alumina bricks and other refractory materials with a SiO ₂ content of 5% or less have a problem in the corrosion resistance in the area where the molten metal enters. However, the present invention is based on the idea that the inner wall 14 of the brick of the filtration chamber 6 for filtering the molten metal such as aluminum, zinc, or copper while heating it with the heater 21 has a silicon nitride-bonded silicon carbide refractory material having excellent corrosion resistance at the portion where the molten metal enters. In FIG. 17, the part where the molten metal does not enter and which receives the radiant heat of the heater 21 is the inner wall of the metal filtration chamber made of the alumina-based refractory or the silicate-bonded silicon carbide-based refractory 18 having excellent oxidation resistance. The portion where the molten metal enters has a structure excellent in corrosion resistance due to the silicon nitride-bonded silicon carbide refractory 17 similar to the conventionally known one, and the portion where the molten metal does not enter and which receives the radiant heat of the heater 21 is excellent in oxidation resistance. Since the refractory material 18 or the silicate-bonded silicon carbide refractory material 18 is used, the effect that it can be used further permanently is exhibited.

[Brief description of drawings]

FIG. 1 is a vertical sectional front view.

FIG. 2 is a cross-sectional plan view.

FIG. 3 is a vertical sectional side view of the filtration unit.

[Explanation of symbols]

1 ... Filtration tank, 2 ... Filtration unit, 3 ... Front plate, 4 ... Rear plate, 5 ... Ceramic tube, 6 ... Filtration chamber, 7 ... Hot water supply port, 8 ... Hot water discharge port, 9 ... Front wall, 10 ... Rear wall, 11 ... Left wall,
12 ... right wall, 13 ... thin iron plate, 14 ... brick inner wall, 15 ...
Ceramic fireproof outer wall, 16 ... Castable layer, 17 ...
Corrosion resistant refractory, 18 ... Oxidation resistant refractory, 19 ... Lid, 20
... Lower surface, 21 ... Heater, 22 ... Communication hole.

Claims (1)

[Utility model registration claims] 1. A brick inner wall of a filtration chamber for filtering a molten metal such as aluminum, zinc, or copper while heating it with a heater, and a portion containing the molten metal is a silicon nitride-bonded silicon carbide refractory having excellent corrosion resistance. An inner wall of a metal filtration chamber in which a portion which does not enter and receives radiant heat of the heater is made of an alumina refractory or a silicate-bonded silicon carbide refractory having excellent oxidation resistance.